1. Field of the Invention.
The present invention relates generally to mixing devices for mixing a two-part fluid compound and, more particularly, relates to such a mixing device which is disposable after use.
2. Description of the Prior Art.
It has been a long-standing problem to provide a packaging kit for packaging or containing a two-part fluid, such as a liquid or semi-liquid. In this context, a semi-liquid contains a high concentration of solids such, for example, as an epoxy which may be loaded with powdered metal. Many of such two-part fluids require mixing immediately before use, and precise metering in predetermined proportions. Among examples are epoxy compounds which when mixed, will harden in a very short period of time. Other examples are certain pharmaceuticals which may have to be precisely metered and mixed or applied in the same spot to provide synergistic action. Some of these liquids or semi-liquids are very viscous; others are not.
It is therefore desirable to provide a disposable mixing chamber for mixing the two liquids or semi-liquids at the point of use. The mixing device, to which the present invention relates may advantageously be used with the disposable shipping containers disclosed in applicant's copending application, Ser. No. 932,054, filed concurrently herewith.
Many mixing devices have been devised in the past. Most of these are rigid, metal-like structures which are permanently installed in some industrial plant. Such a mixer has been disclosed, for example, in the patent to Lyons, U.S. Pat. No. 832,400. The structure is provided with a steel hopper feed and triangularly-shaped bars forming internal passages for the dry mixing of certain cereals, such as rice. A fluid mixer-dispenser is revealed in the patent to Frederick, U.S. Pat. No. 3,746,216. In accordance with the patent, the mixing chamber is disposed internally of a dispensing tube. The mixing ducting has a specified geometry and includes stacked discs and the like. A two-stage mixing is effected by the device. A mixing, homogenizing and emulsifying apparatus is disclosed in the patent to Schmitt, U.S. Pat. No. 3,770,249. Here individual mixing chambers are disposed in series and connected to each other by pipes. Again the apparatus is intended for permanent installation and consists of a steel or metal sandwich structure. Another mixing device is shown in the patent to Clark et al., U.S. Pat. No. 3,861,652. This mixing device includes a series of curved, dividing elements within a hollow tube. The curved elements are spaced from each other by fine mesh screens interposed therebetween. The device is intended for permanent in-line positions, and has two input ports. It could not be used, for example, for laying down beads or a continuous stream of mixed material, such as may be used for connecting different structures to each other by an adhesive.
The patent to Simpson, U.S. Pat. No. 3,941,355, relates to a mixing insert for foam dispensing apparatus. The mixing is effected by a series of lands consisting of discs disposed about an internal shaft in the mixing chamber. Again the device is intended for permanent installation onto a dispenser. Such a device again would not be useful for laying down beads and the like. The patent to Cunningham, U.S. Pat. No. 4,027,857, discloses a static mixer for flowable materials. The mixer is intended for permanent mounting in injection molding equipment. The mixer ducts are made by drilling suitable holes into the mixer element which typically consists of stainless steel. The mixer includes four separate ducts. The patent to Gray, U.S. Pat. No. 4,068,830, is directed to a mixing method and system. It has a tubular mixer of steel with perforated baffle plates internal of the mix stream. The mixer features two inlet ports, and is again, intended for permanent installation.
The patent to Van Sciver II, U.S. Pat. No. 3,159,312, shows a dispensing device for mixing two viscous fluids. It includes flexible, disposable plastic tubing formed to provide a series of duct interchanges with internal fluid-deflecting vanes at the interchanges. The deflecting vanes are disposed only at the fluid interchanges and two separate passageways are provided. The mixing tubes may be formed by electrofusion, welding or thermoplastic injection molding. Bead lay-down or injection with such a device is not practical.
Various other patents relating to mixing devices are provided with flat structures so that a tortuous path is disposed between, say two flat plates. An example of such a device is shown in the patent to Hazlehurst et al., U.S. Pat. No. 3,459,407. The mixer has two separate intake ports, and is intended for permanent installation on fluid feedlines. For the complete mixer, a minimum of three parts is necessary. Contiguous cavities are formed by drilling blind holes. Another flat structure is shown in the patent to Althausen et al., U.S. Pat. No. 3,924,989. It reveals a machine for producing moldings and is intended for permanent installation in an injection molding system. The mixing chamber may be made from slab-like structures with milled-in grooves to form ducts with obstacles. Again a two-port input is used. A device of this type could not be used for laying down beads.
The two patents to Moore, U.S. Pat. No. 3,927,868, and 4,002,289, both disclose a static-type mixer. The mixer is a flat, sheet-strip structure having two-port intake lines. The resulting mixer is a thin, flexible structure which, due to its flexibility, could not be used to direct a stream of mixed fluids and, hence, could not be used for laying down beads and the like.
The patent to Skobel, U.S. Pat. No. 3,623,704, is directed to a static mixing device having a single point of entry and features a pistol-like grip so that it can be held by hand. The mixing device features a very tortuous path which is provided by a plurality of elements which are in turn removable. The pistol grip includes a trigger valving mechanism. The patent to Cochran, U.S. Pat. No. 3,045,984, reveals a fluid blender made of metal for a permanent installation. It is provided with baffles permanently mounted by welding in a hollow tube. The blender is intended for a continuous line flow.
Various other patents relating to mixers show helix-like structures. Among these patents is a Warren patent, U.S. Pat. No. 1,626,487, relating to an emulsifier. The patent discloses a permanent steel structure placed in a fluid feedline. An internal spindle is provided with spiral blades attached thereto for mixing. A somewhat similar mixer construction is disclosed in the patent to Hooker et al., U.S. Pat. No. 2,000,953. Again the mixer consists of a permanent steel structure for mixing gas with semi-fluid materials. A helix is provided which is wound around a central shaft for mixing.